A study from St. Andrews University in Scotland challenges the idea that water is always the best hydrator. It suggests that drinks with nutrients—like milk, which contains sugar, fat, and protein—can help retain hydration longer. For Thai readers facing high temperatures and a wide range of drinks—from iced coffee to herbal brews—this finding offers practical insight: milk may support longer-lasting hydration, but the full story is more complex.
Data from this research shows water is absorbed quickly, but beverages with small amounts of sugar, fat, or protein slow stomach emptying and help water stay in the body longer. Milk stood out because its combination of lactose, fat, protein, and sodium helps conserve fluids. Sodium helps the kidneys retain water, reducing urine output and aiding steadier hydration. This aligns with why oral rehydration solutions, which balance sugar and salts, are recommended for dehydration from illness, a concern for Thai communities during hot seasons.
Dietitian Melissa Majumdar, speaking on the research, notes that electrolytes like sodium and potassium improve hydration, while nutritional content can slow fluid release. She emphasizes that hydration quality depends on beverage composition, not just volume.
However, sugar matters. Thailand ranks among Asia’s top consumers of sweetened drinks. Very high-sugar beverages, such as sodas and some fruit juices, can hamper hydration. In the small intestine, sugars draw water from body tissues to dilute themselves, a process that can promote dehydration despite a momentary refreshment. This is a key message for health messaging around school canteens, public venues, and festival hospitality in Thailand.
Experts warn that sodas and energy drinks often feel refreshing but can be counterproductive during exercise or heat exposure—common experiences for Thais, from Muay Thai training to outdoor work and festival days.
Alcohol is another hydration factor. Light beers, with higher liquid volume and lower alcohol content, cause less fluid loss than spirits, but alcohol nonetheless acts as a diuretic. This nuance is relevant for Songkran celebrations and nightlife safety messaging.
Caffeine also plays a role. Moderate coffee consumption (around one standard cup) can hydrate similarly to water because the body absorbs it well. Diuretic effects are more pronounced at high intakes (above about 300 mg per day), especially for those unused to caffeine. Adding milk to coffee, a common Thai practice, can aid hydration due to the nutrient mix.
Thailand’s Ministry of Public Health’s Nutrition Division has promoted mindful sugary drink consumption, particularly for youth and workers. The new findings may influence upcoming beverage guidelines in schools, universities, and public canteens, encouraging cold, low-fat milk or lightly salted herbal infusions as alternatives to sugary drinks.
Historically, Thai diets featured coconut and other beverages over dairy. Government initiatives since the late 20th century have promoted cow’s milk, especially in schools, as part of nutrition programs. The study invites renewed discussion on the role of different milk products—such as plant-based milks for lactose-intolerant individuals—and hydration benefits in Thai contexts.
Looking ahead, policymakers may weigh this evidence when shaping school meals and public beverage choices, while beverage producers may explore new milk-based options. Experts caution that most people do not need to obsess about exact hydration math; thirst usually prompts adequate intake. Exceptions include athletes, the elderly, and those in heat stress or illness, where balanced fluids and, when needed, medical rehydration solutions are important.
Practical takeaways for Thai households and institutions:
- Water remains the most accessible, calorie-free hydrator for everyday use.
- Unsweetened low-fat milk can support longer-lasting hydration for children, the elderly, athletes, outdoor workers, and people exposed to heat.
- High-sugar drinks offer limited hydration value and can contribute to health issues when consumed excessively.
- Moderate coffee (one to two cups daily, possibly with milk) can count toward daily fluids for most people.
As climate change increases heat exposure in Thailand, staying informed about hydration science matters. For now, balance, regular intake, and awareness of hidden sugars remain essential.
For guidance, refer to Thailand’s health authorities and consult local medical professionals. Listen to your body, choose fluids wisely, and protect family and community health through thoughtful beverage choices.